Autonomous thermal management

ABSTRACT

The present invention provides both a peripheral device that regulates its own temperature by adjusting its power consumption, and a method to accomplish the same. The method generally includes monitoring the temperature of the mass storage device and reducing power consumption when the temperature exceeds a certain threshold.

RELATED APPLICATIONS

This is a divisional application of co-pending prior U.S. applicationSer. No. 10/800,258 (Atty. Dkt. No. APL1P303/P3263), entitled“AUTONOMOUS THERMAL MANAGEMENT”, filed on Mar. 11, 2004, which isincorporated herein by reference and from which priority under 35 U.S.C.§ 120 is claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to data storage devices and, moreparticularly, to temperature management of data storage devices.

2. Description of the Related Art

General-purpose computers require a mass storage system. Unlike mainmemory, which is used for the direct manipulation of data, mass storageis used to retain data. Generally a program is stored in mass storageand, when the program is executed, either the entire program or portionsof the program are copied into main memory. Common mass storage devicesinclude floppy disks, hard disks, optical disks and tapes.

All mass storage devices are designed to operate within certainenvironmental conditions. Temperature is typically the most importantcondition. If temperatures exceed the normal operating conditions, therisk of data loss and file corruption increases, as does the potentialfor total device failure.

In an effort to help users avoid data loss, hard drive manufacturersincorporate logic into their drives that host systems can use to predictpending drive problems. The system is called Self-Monitoring Analysisand Reporting Technology or SMART. The hard disk's integrated controllerworks with various sensors to monitor various aspects of the drive'sperformance and makes available status information to software thatprobes the drive and look at it. SMART monitors disk performance, faultysectors, recalibration, CRC errors, drive spin-up time, drive heads,distance between the heads and the disk platters, drive temperature, andcharacteristics of the media, motor and servomechanisms.

The hard drive itself does not actually do anything with SMART data, itmerely makes the information available to the host upon request. It isup to the host to request and analyze the data, and typically up to theuser to take appropriate action. In other words, a program, such asNorton Utilities from the Symantec Corporation of Cupertino, Calif., isrequired to initiate a SMART request, utilize the SMART data, and thennotify the user of any potential problems.

SMART data is, of course, not the only way to get temperature data froma mass storage device. Temperature sensors from a separate device can beused to probe a mass storage device's temperature. Many commerciallyavailable cooling systems that use fans and/or heat sinks to control ahard drive's temperature also use temperature sensors to reporttemperature to the user.

Although the described technologies work well in many applications,there are continuing efforts to further improve the ability to monitorand regulate device temperatures.

SUMMARY OF THE INVENTION

The present invention provides both a peripheral device that regulatesits own temperature by adjusting its power consumption, and a method toaccomplish the same. In one embodiment of the invention, the methodincludes monitoring the temperature of the mass storage device andreducing power consumption when the temperature exceeds a certainthreshold. In such an embodiment, the mass storage device would becapable of operating while the power consumption is reduced.

In another embodiment, the method includes reducing offline diagnosticactivities if the temperature of the peripheral device exceeds a firsttemperature, reducing an operational speed in which the peripheraldevice fulfills requests from a host device if the temperature of theperipheral device exceeds a second temperature and reducing powerconsumption of a physical layer interface that connects the peripheraldevice to the host device if the peripheral device exceeds a thirdtemperature and if the peripheral device experienced a period ofinactivity that exceeds a first time threshold. In yet otherembodiments, the temperature in a hard drive can be further reduced byparking heads of the hard drive if a temperature threshold and a timethreshold are exceeded.

In yet other embodiments, a hard drive that autonomously manages itstemperature is described. The hard drive includes a hard platter thatrotates, a magnetic medium that stores information, heads that read andwrite information to the magnetic medium, an arm that holds the heads, atemperature sensor that measures temperature and an integratedcontroller. The integrated controller that can reduce power consumptionwhen the temperature exceeds a certain threshold, wherein the hard driveis capable of operating while the power consumption is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by reference to the followingdescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1A depicts an exemplary general-purpose computer system that canutilize the invention;

FIG. 1B depicts an abstracted representation of the general-purposecomputer system of FIG. 1A;

FIG. 2 depicts an improved hard drive, one embodiment of the improvedmass storage device of FIG. 1B; and

FIGS. 3A through 3C are representational flow charts illustrating onetechnique that can be used to implement various power-reductionmechanisms in the improved hard drive of FIG. 2.

It is to be understood that, in the drawings, like reference numeralsdesignate like structural elements. Also, it is understood that thedepictions in the figures are not necessarily to scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, numerous specific details are set forth toprovide a thorough understanding of the present invention. However, itwill be obvious to one skilled in the art that the present invention maybe practiced without some or all of these specific details. In otherinstances, well known process steps have not been described in detail inorder to avoid unnecessarily obscuring the present invention.

FIG. 1A depicts an exemplary general-purpose computer system 100 thatcan utilize the current invention. Components include a computer 105,various input devices such as a mouse 110 and keyboard 115, and variousoutput devices such as a monitor 120 and a printer 125.

FIG. 1B depicts an abstracted representation of a computer system 100 ofFIG. 1A that depicts its essential components. A single component 130represents input devices that allow a user to interact with the computersystem 100, such as a mouse and keyboard. Similarly, a single component135 represents the output devices that display what the computer system100 has accomplished, such as a monitor and printer. The heart of thecomputer system 100 is a central processing unit (CPU) 140, and is thecomponent that executes instructions. Main memory 145 is typicallyvolatile and provides the CPU 140 with both the instructions to beexecuted and data to be manipulated by the instructions. Thesecomponents 130, 135, 140, and 145 are all well known in the art.

An improved mass storage device 150 allows the computer system 100 topermanently retain large amounts of data. The components 130, 135, 140,145, and 150 are able to exchange information with each other via a hostbus 155.

FIG. 2 depicts an improved hard drive 200, which is one embodiment ofthe improved mass storage device 150. The components that are shown inFIG. 2 are a hard platter 205, which is the spinning disk that holds amagnetic medium that stores information, an arm 210 that holds theread/write heads and is able to move the heads from the hub to the edgeof the drive, and a cut-away portion of the disk enclosure 215 thatcovers and protects the internal components of the hard drive (e.g., 205and 210).

Different hard drives report different temperatures in response to anappropriate SMART request. Some manufacturers may attach temperaturesensors directly to the disk enclosure 215 and report temperatures ofthe disk enclosure 215. Other manufactures may include temperaturesensors in the circuit board that contains the hard drive's integratedcontroller. Internal temperatures are typically about two degrees hotterthan the temperature of the disk enclosure 215. Accordingly, ifprecision were required when using SMART data, such variations inreporting temperature would need to be accounted for when determiningsafe operational temperatures.

The improved hard drive 200 preferably has an integrated controller thatinterprets temperature data and autonomously reduces the device's powerconsumption. Power is “consumed” in an electric circuit by beingconverted into other forms of energy—typically heat, light, and/ormotion. Reducing power consumption, therefore, has the effect ofproducing less heat, allowing the device to cool to the ambienttemperature.

Table 1 lists exemplary actions that can be taken to reduce powerconsumption, sorted from the least intrusive to the most intrusiveactions. TABLE 1 Action Power (approx.) Suspension of offline activities2 W Reduction of seek speed 2 W Reduction of PHY operating mode (Activeto Partial) 1 W Parking of drive heads 1.5 W   Reduction of PHYoperating mode (Partial to Slumber) 1 W Changing drive state 4 W

Although all of the actions listed in Table 1 have some effect on thefunctionality of the improved hard drive 200, it is generally moreimportant to keep the device within its operating conditions than tohave access to full functionality. As previously described, SMART isused for a variety of diagnostic concerns. Under normal conditions, theSMART defect scan is always running as a background operation. However,the improved hard drive 200 has the ability to suspend such offlineactivities when the device temperature exceeds certain parameters.Although the device looses the ability to identify certain problems, theuser's experience is largely unaffected. Once the device temperaturefalls back into a safe zone, the offline activities can resume.

If the device temperature continues to increase, more intrusive measurescan be taken. For example, changing the seek speed from “performanceseek mode” to “silent seek mode.” Although not all hard drives may havethe option to change operating modes, drives available from SeagateTechnology, Inc of Scotts Valley, Calif., advertise Sound BarrierTechnology or SBT. Although sound appears to have been the main concernfor implementing SBT, a byproduct of silent seek mode is less power isconsumed.

It should be noted that both suspending offline activities and reducingseek speed could be done without notifying the host system. The hostsystem will treat the improved hard drive 200 the same, regardless ofwhether offline activities have been suspended and seek speed has beenreduced. However, changing the PHY interface's operating mode is anaction that would be seen by the host.

Serial ATA specifications define three separate PHY interface modes thatare used for power management: active, partial and slumber. The improvedhard drive 200 could initiate a reduced-power mode in response to atemperature threshold being reached. Serial ATA allows for either a hostor an attached device to initiate a change in the PHY operating mode.

Another mechanism that can be used to reduce the power consumption ofthe improved hard drive 200 is parking the drive heads and disablingposition servo electronics. Normally, a hard drive is configured to keepthe read/write heads on track so that information from the same sectorcan be quickly accessed. However, parking the heads can save power bytrading off a bit of speed.

The most intrusive mechanism listed in table 1 is changing the drivestate from active to standby. In standby mode, a hard drive's spindlemotor is typically disabled. The spindle is the rotating hub structureto which the discs are attached. The spindle motor is theelectromechanical part of the disc drive that rotates the platters.Although the spindle motor would need to be enabled before anyoperations could be performed, temporarily disabling the spindle motorsresults in a fairly large power reduction.

FIGS. 3A through 3C are representational flow charts illustrating onetechnique that can be used to implement the various power-reductionmechanisms that are enumerated in Table 1. At 305 the improved harddrive 200 continuously monitors both its temperature and the elapsedtime since the host last sent a command. Certain power-saving techniquesrequire long wake-up times to resume functionality. As will be morefully described later, these techniques would typically not be used ifthe storage device were being continuously accessed.

At 310 the system determines whether a first temperature threshold wasreached. Before this threshold is reached, at 315 the improved harddrive 200 fully implements all offline activities. However, once thetemperature reaches a first threshold, it suspends the offlineactivities at 320. The first temperature threshold can be keyed to theoperating parameters of the improved hard drive 200. For example, if theimproved hard drive 200 is subject to increased risk of failure attemperatures over 65° C., then a good choice for the first temperaturethreshold might be about 50° C.

After the first threshold is reached, the system continues to monitorwhether the temperature reaches a second threshold at 325. As long asthe system temperature is between the first and the second thresholds,the only remedial action the improved hard drive 200 would take issuspending the offline activities. Once the temperature reaches thesecond threshold, the silent seek mode would be initiated at 330. Ifsuspending the offline activities and reducing the seek mode succeededin reducing the temperature, then the improved hard drive 200 can revertto performance seek mode at 335. The second threshold might be a fewdegrees over the first threshold. If the second threshold were equal tothe first threshold, then the suspension of offline activities and thereduction of the seek mode would occur simultaneously.

At 340 the system determines whether a first time threshold has beenreached. Generally, the time threshold would be related to the amount oftime necessary to revert the system back to operational status from theremedial action. The remedial action at 350 is placing the interfaceinto a partial PHY operating mode from the active PHY operating mode.Since it only takes a few microseconds to wake the interface up frompartial to active, an appropriate first time threshold might be about 5seconds of inactivity. The improved hard drive 200 checks whether theinterface is active PHY mode at 345 prior to placing the interface intopartial PHY mode so that the system does not inadvertently increase thepower consumption by upgrading the interface from slumber mode intopartial mode (placing the interface into slumber mode is described laterat 370). The interface would typically revert back to active mode at thenext disk access. Alternatively, logic can be implemented that revertsthe interface back to active mode if the temperature drops below athreshold temperature.

At 355 the system determines whether a third temperature and a secondelapsed time threshold is reached. If both thresholds are reached thenat 360 the improved hard drive 200 will park its heads and disable theservo electronics until the next disk access (or, alternatively, untilthe temperature drops below some predefined level). The thirdtemperature threshold might be a few degrees over the second temperaturethreshold and the second elapsed time threshold might be from 30 secondsto a minute.

At 365 the system determines whether a third elapsed time threshold isreached, which can be between two and five minutes of inactivity. Ifenough time has passed, and the temperature still needs to be reduced,then the improved hard drive 200 would initiate a slumber PHY operatingmode request at 370.

Similarly, at 375 the system determines whether a fourth temperaturethreshold and a fourth time threshold is reached. The temperaturethreshold might be a few degrees below the maximum temperature for theimproved hard drive 200, and the elapsed time can be between five andten minutes of inactivity. At 380 the system would initiate the standbydrive state until the next disk access. If such measures do not reducethe temperature, and the temperature exceeds the maximum operatingtemperature for the improved hard drive 200, then drastic actions mightneed to be taken, such as shutting down the drive or notifying the hostthat it must take immediate remedial actions.

Generally, the techniques of the present invention may be implemented onsoftware and/or hardware. For example, they can be implemented in anoperating system, in a separate user process, in a library package boundinto network applications, or on a specially constructed machine. In aspecific embodiment of this invention, the technique of the presentinvention is implemented in software embedded within the control systemof a mass storage device.

Because such information and program instructions may be employed toimplement the systems/methods described herein, the present inventionrelates to machine-readable media that include program instructions,state information, etc. for performing various operations describedherein. Examples of machine-readable media include, but are not limitedto, magnetic media such as hard disks, floppy disks, and magnetic tape;optical media such as CD-ROM disks; magneto-optical media such asfloptical disks; and hardware devices that are specially configured tostore program instructions, such as read-only memory devices (ROM) andrandom access memory (RAM). The invention may also be embodied in acarrier wave traveling over an appropriate medium such as airwaves,optical lines, electric lines, etc. Examples of program instructionsinclude both machine code, such as produced by a compiler, and higherlevel code that may be executed by the computer (e.g., using aninterpreter).

Although illustrative embodiments and applications of this invention areshown and described herein, many variations and modifications arepossible which remain within the concept, scope, and spirit of theinvention, and these variations would become clear to those of ordinaryskill in the art after perusal of this application. For example, thetimes, temperatures and remedial actions described above can be easilyadjusted to operate in different conditions. Accordingly, the presentembodiments are to be considered as illustrative and not restrictive,and the invention is not to be limited to the details given herein, butmay be modified within the scope and equivalents of the appended claims.

1. A method for a peripheral device to regulate its temperature byregulating its power consumption, comprising: reducing offlinediagnostic activities if the temperature of the peripheral deviceexceeds a first temperature; reducing operational speed in which theperipheral device fulfills requests from a host device if thetemperature of the peripheral device exceeds a second temperature; andreducing power consumption of a physical layer interface that connectsthe peripheral device to the host device if the peripheral deviceexceeds a third temperature and if the peripheral device experienced aperiod of inactivity that exceeds a first time threshold. 2-9.(canceled)
 9. The method of claim 8, wherein the fourth temperature ishigher than the third temperature.
 10. A method for regulatingtemperature in a mass storage device comprising: monitoring thetemperature of the mass storage device; and reducing power consumptionwhen the temperature exceeds a certain threshold; wherein the massstorage device is capable of operating while the power consumption isreduced.
 11. The method of claim 10, wherein the mass storage device isa hard drive.
 12. The method of claim 11, wherein the power consumptionis reduced by suspending offline diagnostic activitites.
 13. The methodof claim 11, wherein the power consumption is reduced by reducing seekspeed of the hard drive.
 14. The method of claim 11, wherein: the harddrive has a physical layer interface that connects the peripheral deviceto a host device, the physical layer interface has different powermodes; the power consumption is reduced by changing the power mode ofthe physical layer interface.
 15. The method of claim 14, wherein thepower mode is changed only if a period of inactivity where the hostdevice has not used the hard drive has elapsed.
 16. The method of claim15, wherein the power mode reverts back to its original mode when thehost attempts to use the hard drive.
 17. The method of claim 14, whereinthe power mode is changed from active to partial.
 18. The method ofclaim 14, wherein the power mode is changed from partial to slumber. 19.The method of claim 11, wherein the hard drive can be placed into astandby state, and wherein power consumption is reduced by placing thehard drive into the standby state if a period of inactivity where thehost device has not used the hard drive has elapsed.
 20. A hard drivethat autonomously manages its temperature comprising: a hard platterthat rotates; a magnetic medium that stores information; heads that readand write information to the magnetic medium; an arm that holds theheads; a temperature sensor that measures temperature; an integratedcontroller that can reduce power consumption when the temperatureexceeds a certain threshold, wherein the hard drive is capable ofoperating while the power consumption is reduced.